Positive on position indicator

ABSTRACT

A molded case circuit breaker having spring powered over-center toggle contact operating mechanisms is provided with means to prevent the operating handle from moving to its off position unless the contacts are open. This means may engage the toggle near the knee thereof to assist in driving the toggle over center during opening movement of the handle.

United States Patent [1 1 Brumfield Jan. 1, 1974 I5 POSITIVE ON POSITIONINDICATOR 5.194900 7/1905 Epstein 200/010. 42 ux 0 [75] Inventor: JohnC. Brumfield, Drexel H Pa 3,l8..,l57 5/l965 Brumficld .I 200/1536A$5lgnee5 pg Corporation, Primary Examiner-J. R. Scott Philad lphAssistant Examiner-Robert A. Vanderhye [22] Filed July 27 1972Att0rneySidney G. Faber et al.

21 A l. N 275 622 1 pp 0 [57 ABSTRACT 52 U.S. Cl. 200/153 G, 200/1310.42 A molded case drcu" breaker having Spring POwered 51 Im. Cl. H01h3/46 Over-Center mggle Operating mechanisms is 58 Field of Search...ZOO/DIG. 42; 153 G, Provided with means 1mm"t the Operating handle200/153 H, 67 PK, 167 337/59; 335/191 from 'moving to its off positionunless the contacts are open. This means may engage the toggle near theknee [56] References Cited thereof to assist in driving the toggle overcenter dur- UNITED STATES PATENTS ing opening movement of the handle.3,605,051 9/1971 Casey et al ZOO/DIG. 42 UX 9 Claims, 10 Drawing FiguresPATENTEDJAX 1 m4 SHEET 30$ 6 PATENTEDJAK I I974 SHEET 5 (If 6 POSITIVE NPOSITION INDICATOR This invention relates to circuit breakers havingspring powered contact operating mechanisms and relates moreparticularly to circuit breakers of this type having novel means toprevent the circuit breaker handle from indicating an off conditionunless the contacts are actually separated.

In many circuit breakers having over-center toggle type contactoperating mechanisms, it is possible to move the handle to the off oropen circuit position even though the contacts are closed because ofwelding or otherwise. This creates a dangerous condition because aserviceman will feel confident that the load-circuit being protected bythe breaker is deenergized.

The prior art has sought to cope with this condition by constructingso-called visible break switches. In some cases inspection of thecontacts of visible break switches requires the housing to be open. Inother cases the housing may have a transparent part through which thecontacts are visible, but this part soon becomes dirty so that view ofthe contacts becomes obstructed. In any event, the aforesaid prior artconstructions require the servicemen to perform an extra procedure todetermine whether the contacts are really open.

This invention provides a lever that positively prevents the handle fromassuming its off position unless the contacts are open. In particular,this lever is connected between the operating member and frame of thecontact operating member in such a manner that movement of the handletoward its off position moves the lever so that a projection thereonmoves toward the knee of the mechanism toggle. The toggle will collapseonly if the movable contact carrier moves to open circuit position.

Thus, if the contacts open, the toggle will collapse and will not blockmovement of the lever projection as the lever is moved by the handle asthe latter moves toward its off position. However, if the contactsremain closed for any reason, the toggle cannot collapse and in theextended position thereof will block movement of the lever projection.This prevents movement of the lever which in turn prevents the handlefrom moving to its circuit open position.

Accordingly, a primary object of the instant invention is to providenovel means to prevent a circuit breaker handle from moving to its offposition while the contacts remain closed.

Another object is to provide means of this type especially constructedfor use with a spring powered overcenter toggle contact operatingmechanism.

Still another object is to provide means of this type consisting of alever whose movement is restrained by the toggle when extended and undersuch conditions the lever restrains movement of the operating handle toits open position.

These objects as well as other objects of this invention will becomereadily apparent after reading the following description of theaccompanying drawings in which:

FIG. I is a plan view of a circuit breaker constructed in accordancewith teachings of the instant invention.

FIG. 2 is a longitudinal cross-section taken through line 2-2 of FIG. 1,looking in the direction of arrows 2-2 and including a handle operatingmechanism, not shown in FIG. 1.

FIG. 3 is an exploded perspective of one overcenter toggle mechanism andselected elements connected thereto.

FIG. 4 is an exploded perspective of the movable contact structure forone pole.

FIG. 5 is a side elevation of the spring supporting operating member ofthe contact operating mechanism.

FIGS. 6 and 7 are plan and side elevations respectively of the operatingmember of FIG. 5, looking in the directions of the respective arrows 6-6and 7-7 of FIG. 5.

FIG. 8 is a side elevation of the contact operating mechanism for onepole with the near side of the frame removed.

FIG. 9 is an end view of one side of the mechanism frame showingmounting of a positive ON indicator lever and the position of the latterrelative to elements of the mechanism that cooperate with this lever.

FIG. 10 is an enlarged fragmentary longitudinal cross-section of thehandle showing its mounting to the operating member of the center pole.

Now referring to the figures. Three phase molded case circuit breaker 25of FIGS. 1 and 2 includes an individual over-center spring-poweredtoggle operating mechanism. Prior art examples of circuit breakershaving more than a single operating mechanism for all phases aredisclosed in U. S. Pat. Nos. 2,067,935 and 3,125,653.

Circuit breaker 25 includes a molded housing constructed of base 26 andremovable cover 27 joined along line 28 and provided with longitudinalinternal partitions 31, 32 which divide housing 26, 27 into threelongitudinally extending compartments, one for each phase of circuitbreaker 25. Cover 27 is provided with aperture 29 through which stubbybifurcated extension 33 of operating handle means 30 extends. Eachsection of handle extension 33 receives an individual pin 34 extendingupwardly from the web portion ofinverted generally U-shaped operatingyoke member 35 of the center phase. Operating members 35 of the outerphases are each secured to handle means 30 by a pair of screws 152.

Member 35 is pivoted to the spaced arms of generally U-shaped operatingmechanism frame 36 at outwardly extending lugs 37. Bolts 48, received bythreaded apertures of inturned edges 36a at the bottom of frame 36,fixedly secure the latter to base 26. Transverse tie member 49 isriveted to the arms of frame 36 to maintain spacing therebetween and tostabilize the frame structure.

Four-tensioned coil springs 38, each connected at one end thereof to theweb of operating member 35, combine to constitute the main operatingspring means for the overcenter toggle-type contact operating mechanism.The other ends of springs 38 are connected to spaced plates 39, 39 thatare pivotally mounted to toggle knee pin 41 connecting upper 42 andlower 43 toggle links. The upper ends of upper toggle links 42 arepivotally connected to the spaced arms of latchable cradle 40 at pins44, and the lower ends of lower toggle links 43 are pivotally connectedto contact carrier 45 by rod 46 that extends between the spaced arms ofcontact carrier 45. The spaced arms of cradle 40 are positioned adjacentthe inner surfaces of the spaced arms of frame 36 and are pivotallyconnected thereto by pins 47 that are secured to frame 36.

Under normal operating conditions plate 51, secured to web 40a of cradle40, is in engagement with forward latching surface 52 of auxiliary latch53. The latter is loosely mounted to pivot rod 55 extending between thespaced arm of mechanism frame 36 and slightly outboard thereof. Thecoiled end sections of torsion spring member 56 are wound about pivotrod 55, with the ends of these sections bearing against rod 57 andauxiliary latch 53 to bias the latter counterclockwise against stop rod58. The ends of rods 57 and 58 are supported by the arms of frame 36.Leaf spring 73 secured to auxiliary latch 53 bears against pivot rod 55biasing latch 53, so that rod 55 will normally lie at the centralportion of V-shaped notch 74 of primary latch 53.

The ends of rod 55 projecting outboard of mechanism frame 36 are engagedby the hooked portions at the forward extension 59 of the arms forU-shaped trip unit frame 60, whose web portion is seated on a forwardsurface of load strap 61, being secured thereto by bolts 62 that extendthrough clearance apertures in strap 61 and are received by threadedinserts molded in base 26.

Rear latch tip 54 engages latch tip 63 at the U-shaped forward arm ofprimary latch 65, whose rear latch tip 64 is engaged by latch plate 67mounted on one leg of L-shaped carrier 66. Primary latch 65 is pivotallymounted to trip unit frame 60 at stub shaft 69, and the carrier ispivoted on rod 68 to frame 60. Tension spring 75 biases primary latch 65in a clockwise direction about pivot 69. Theother leg of carrier 66 isprovided with transversely extending pin 71 that projects intotriangular window 72 of primary latch 65 at a portion thereof near rearlatch tip 64, for a reason to be hereinafter explained. Tension spring76, connected between frame 60 and carrier extension 66a, biases carrier66 in a'counterclockwise direction about its pivot 68 toward latchingposition.

When automatic tripping occurs, carrier 66 in the faulted phase is movedclockwise either by the deflection of bimetal 77 or movement of magneticarmature 78, causing latch plate 67 to release primary latch 65, whichin turn releases secondary latch 53 and permits main operating springs38 to rotate cradle 40 in a counterclockwise direction to break toggle42, 43. The force from main spring 38 acts through cradle 40, primarylatch 53, and secondary latch 65 to drive cam surface 78, boundingopening 72, against extension 71 to rotate carrier 66 clockwise, withsurface 79 thereof engaging ear 81 of extension 82 on tripper bar 80which extends between all three phases. This causes tripper bar 80 torotate in a counterclockwise direction, so that extensions 82 in thenon-faulted phases rotate counterclockwise with cam surfaces 83 thereofengaging transversely extending pin 84 of carriers 66 in the nonfaultedphases, rotating them clockwise or in the trip ping direction, torelease the cradle latching systems in the non-faulted phases, so thatthe contacts of all three phases are open.

In order to prevent closing of the contacts of any one phase before theoperating mechanisms of all phases are latched, circuit breaker 25 isprovided with a defeater latching system including defeater latch 80'and defeater lever 90. Latch 80' is pivotally mounted upon rod 55 andincludes protrusion 81' extending over the rear of cradle 40 when thelatter is in latched position. Latch 80' further includes protrusion 82'extending over the forward end of defeater lever 90 in slot 91 thereof.Coiled tension spring 83 is connected between stop rod 57 and latchpassing partially around rod 55, to bias latch 80 in a counterclockwisedirection about its pivot 55 and maintaining this pivot in the basicposition at the right end of slot 84 in latch 80. This basic position isestablished through the engagement of latch stop surface 86 and stop rod57.

Slot 91 is in the web of the U-shaped forward portion of latch lever 90,with the U arms having pivot pin 69 for lever extending therethrough.Rear portion 89 of lever 90 is positioned below and in interferingrelationship with transverse pin 71 mounted to latch plate carrier 66.

During normal relatching of circuit breaker 25, inwardly protrudingportions of the operating member 35 arms engage outboard portions of pin44 to pivot cradle 40 clockwise, whereby the latter cams defeater latch80' away and moves below auxiliary latch 53. Upon release of the circuitbreaker operating handle 30, the elements of the latch train 53, 65, 66move into place. However, should any of these elements fail to properlyengage or should cradle 40 not have been moved far enough to engageauxiliary latch 53, cradle 40 will pick up defeater latch protrusion81', causing clockwise rotation of defeater latch 80. In turn, thiscauses defeater latch protrusion 82 to engage defeater lever 90 androtate the latter counterclockwise, with the rear end 89 thereofcontacting carrier extension 71 so that latch plate carrier 66 ispivoted in a clockwise or latch train releasing direction. During thisreleasing movement of carrier 66, surface 79 thereof engages nose 81 ofone trip bar extension 82 to rotate common tripper bar 80 in acounterclockwise direction, with the other extensions 82 on bar 80engaging pins 84 on the latch plate carriers 66 of the other poles,thereby causing the latch systems of all other poles to be released.

The lower end of bimetal 77 is fixedly secured to shading coil 99, andthese elements are fixedly secured to molded frame member secured totrip unit frame 60. The horizontal leg of inverted U-shaped stationarymagnetic frame member 98 passes through the center of coil 99. Member 98is secured to the rear of frame 60, with the vertical legs of member 98being on opposite sides of load strap 61. The other U-shaped magneticframe member 96 is secured directly to load strap 61, with the ends ofthe arms for frame members 96 and 98 confronting one another in spacedrelationship. Thus, current flowing in load strap 61 generates flux inmagnetic frame 96, 98 which induces current flow in shading coil 99 andthereby generates heat that is conducted to bimetal 77 for heatingthereof. Coiled tension spring 97, connected between armature 78 and anelement mounted to the rear transverse part 60a of frame 60, biases theformer away from two spaced legs 98a extending upward from thehorizontal leg of member 98, and is drawn downward toward legs 98a whenoverload currents generate sufficient magnetic flux in magnetic frame78, 96, 98.

With particular reference to FIG. 4, it is seen that the movable contactstructure for each phase of circuit breaker 25 includes eight maincontacts 103-110 and a single arcing contact 101. The latter contact 101is mounted at the forward end of arm 112, which is pivotally mounted tocarrier 45 at toggle connecting rod 46. Main contacts 103-110 arearranged in two parallel rows positioned to the rear of arcing contact101 and disposed at right angles to the plane of movement of arcingcontact arm 112.

Main contacts 103-106 in the forward row are mounted to individualcontact arms 113-116 respectively, all pivotally mounted to carrier 45on rod 46. Main contacts 107-110 in the rear row are mounted to theforward end of the respective contact arms 117-120, respectively,pivotally mounted to carrier 45 on rod 102. All of the contact arms112-120 are connected to load strap 61 by means of individual stacks 121of flexible sheet conductors. Contact arms 113-116 are in alignment withand extend over therespective contact arms 117-120, so that the lattergroup of arms 117-120 block downward movement of the former group ofarms 113-116 to establish the open circuit position of contacts 103-106in a manner which will hereinafter be seen. The open'circuit positionfor arcing contact arm 112 is established through engagement thereofwith aligned pins 123, 124 which mount the respective pairs of maincontacts 117, 118 and 119, 120 to auxiliary carriers 125, 126respectively. Notch 122 along the lower edge of arcing contact arm 112provides clearance for pins 123, 124.

Auxiliary carrier 125 is an inverted U-shaped member whose arms extenddownwardly through cutouts 131, 132 in the web portion of contactcarrier 45 and straddle four contact arms 113, 114, 117, 118. Pin 123secures contacts 117, 118 to the lower ends of the arms comprisingauxiliary carrier 125. The web of auxiliary carrier 125 is biasedtowards the web of contact carrier 45 by coiled compression spring 127,which is wound around the threaded body of bolt 128 whose head ispositioned below the web portions of contact carrier 45. Self-lockingnut 133 mounted to bolt 128 is rotated to adjust the loading of spring127, with the rectangular shoulder of bolt 128 cooperating withrectangular cutout in carrier 45 to prevent rotation of bolt 128. Thusit is seen that in the open circuit position, spring 127 biases the webof auxiliary contact carrier 125 against the web of contact carrier 45,and when the contacts are closed there is a space between the webs ofthese contact carriers 45, 125, so that the force exerted by spring 127acts to bias contacts 107, 108 into firm electrical engagement withtheir respective cooperating contact portions on line strap 136.

The mounting of contact arms 119, 120 to auxiliary contact carrier 126and mounting of the latter to contact carrier 45 is the same as themounting of contact arms 117, 118 and auxiliary carrier 125, so thatthis description will not be repeated. Biasing forces for each of'thecontacts 103-106 in the forward row are provided by individual coiledcompression springs 138, and each ,of these springs is mounted in thesame way so that only the mounting of one of these springs will bedescribed. The lower end of spring 138 extends into depression 139 inthe upper surface of main contact arm 1 13, and the rear of spring 138extends into tubular support 141 through the open bottom thereof.Support 141 is mounted to the upper surface of carrier 45 at the webportion thereof, and its upper end is threaded to receive adjustingscrew 142 whose lower end bears against disc 143 abutting the upper endof spring 138. If screw 142 is adjusted to set the contact pressureexerted by spring 138, lock nut 144 is tightened to lock thisadjustment.

In order to increase the area of engagement between main contacts103-110 and their respective cooperating stationary main contacts in thevery limited space available, it is noted that each of themain contactsis provided with a portion extending outward of its respective contactarm. That is, in order to utilize the space below arcing contact 112,main contacts 104, 105, 108, 109 have been extended beyond theirrespective contact arms 114, 115, 118, 119 to project below arcingcontact arm 112. Similarly, main contacts 103, 106, 107, 1 10 have beenextended outboard from their respective contact arms 1 13, 1 16, 117,120, to lie in the space below the outboard arms of auxiliary contactcarrier 125, 126 and other elements used to connect the movable contactstructure to the contact operating mechanism.

The forward end of arcing contact arm 112 is biased downward away fromthe web portion of contact carrier 45 by coiled compression spring 171whose lower end is positioned by pin 172 extending upward from arm 112.The upper end of spring 171 extends into tubular member 173, on theupper surface of the carrier 45 web portion, through the bottom ofmember 173 and abuts the closed upper end thereof.

The spaced arms of contact carrier 45 are provided with rearwardextensions 45a, 45b that are spaced by and secured to shoulderedcylindrical tube 146. After all contact structures, operatingmechanisms, latching devices, and automatic trip units are mounted tobase 26, and all adjustments to these mechanisms have been made, thecontact structures of all phases are operated to the closed circuitposition, so that the tubular members 146 of all phases are axiallyaligned and are positioned above barriers 31, 32 and the longitudinalsides of base 26. Thereafter, cylindrical tie bar 147 is drivenlongitudinally in the members 146 of all phases to con- 7 stitute arigid mechanical connection between the movable contact structures ofall phases. The fit between tie rod 147 and tubular members 146 is tightenough to prevent unintentional axial movement of tie rod 147, yetpermits tie rod 147 to be removed for convenient servicing andreplacement of parts. Mechanism frame 36 is provided with alignedelongated slots 148 to provide clearances for movement of rod 147 duringopening and closing of the movable contact structures.

The construction of operating member 35 is best seen by reference toFIGS. 5-9. In particular, inverted U-shaped operating member 35'includesspaced arms 201, 202 connected at their upper ends by web 203. Each armis provided with an inwardly extending cradle engaging resettingprotrusion 204, and an elongated slot 205 which receives outwardlyextending pin 211 at the upper end of an individual S-shaped lever 210which, as will hereinafter be described, functions as the key element ofa positive ON indicating means. Web 203 is provided with four pairs ofapertures 213, 214 through which the upper ends of springs 38 arehooked. Threaded apertures 215 in web 203 receive the threaded ends ofshoulder pins 34 (FIG. 10) in the case of the center pole mechanism, andfor the outer poles threaded apertures 215 receive fastening bolts 152.

The lower or free end of each arm 201, 202 is providecl with a pair ofarcuate bearing notches 238, 239. During assembly of the contactoperating mechanism, frame supported bearing studs 37 are received bybearing notches 238, and in this position of operating member 35springs38 are substantially relaxed, thereby permitting the mechanism elementsto be moved readily to positions where they may be assembledconveniently.

After the mechanism elements are assembled, operating member 35 is movedto a new position wherein bearing studs 37 are received by arcuatenotches 239. This repositioning of operating member 35 fully loadssprings 38 forcontact operation and contact pressure. This increase inspring pressure results from the fact that the distance between web 203,and operating bearing notch 239 is greater than the distance betweenassembly bearing notch 238 and spring supporting web 203, so that therepositioning of operating member 35 moves the upper ends of main springsections 38 away from the lower ends thereof which are secured tomembers 39 pivotally mounted on toggle knee. Each S- shaped lever 210 ispivotally mounted to a pin 209 extending outward from the side ofmechanism frame 36 (See FIGS. 8 and 9). At a point between pivot 209 andpin 211, lever 210 is provided with pin means 212 extending inwardlythrough a clearance aperture 191 in frame 36 to cooperate with lowertoggle link 43 and prevent operating member 35, and handle 30 securedthereto, from moving to a contact open position unless the contacts areactually open.

More particularly, when handle 30 is moved in a clockwise direction withrespect to FIG. 8 to open circuit breaker 25, acting through pin 211 inslot 205, operating member 35 moves lever 210 clockwise about pivot 209.This moves pin 212 on lever 210 toward knee 41 of toggle 42, 43.However, unless toggle 42, 43 collapses, and this may only occur whencontact carrier 45 moves to open circuit position, lower toggle link 43blocks movement of pin 212 so that pin 211 prevents handle 30 frompivoting clockwise to open circuit position. In the event there is aminor malfunction of the contact operating mechanism causing carrier 45to stick in contact closed position, the engagement of pin 212 with link43 may collapse toggle 42, 43 to bring about contact opening.

The constructions and functions of insulating disks 235, 236 (FIG. 10)mounted on movable contact tie bar 147, and barrier sheets 231, 232mounted to handle by screws 230 are described in one or more of thecopending applications referred to in the following paragraph of thisapplication. Similarly, the constructions and functions of roller 222and washers 223 all mounted to handle extension 33 by roll pin 233 aredescribed in one or more of the aforesaid copending applications.

For those features of construction in circuit breaker 25 that have notbeen described in detail herein, reference is made to one or more of thecopending applications Ser. Nos. 275,568, 275,577, 275,446, 275,578,275,507, 275,454, 275,508, 275,621, 275,623,

- 275,624, 275,569, 275,522, 275,52l, and 275,523, all

filed of even date herewith, and all assigned to the assignee of theinstant invention.

. Although there has been described a preferred embodiment of this novelinvention, many variations and modifications will now become apparent tothose skilled in the art. Therefore, this invention is to be limited notby the specific disclosure herein but only by the appending claims.

The embodiments of the invention in which an exclusive privilege orproperty is claimed are defined as follows:

l. A circuit breaker including cooperating contact means, an overcentertoggle mechanism for moving said contact means between open'and closedpositions,

and a handle operable between circuit breaker ON and OFF positionscorresponding to the respective open and closed positions of saidcontact means; said mechanism including toggle means operativelyconnected to said contact means, main spring means operatively connectedto said toggle means to furnish opening and closing forces for saidcontact means, and an operating member connected to said handle andmovable therewith to change the relative positions of the line of actionof said means and the knee of said toggle means for driving the togglemeans overcenter thereby opening and closing said contact means; pivotedlever means connected to said operating member and having a partcooperating with said toggle means to block movement of said lever meansin a first direction until said toggle means is collapsed in a contactmeans opening direction; with movement of said lever means in a firstdirection being blocked by said toggle means, said lever means actingthrough said operating member restraining said handle from moving to itssaid OFF position; said mechanism also including a frame; one end ofsaid lever means being pivotally mounted to fixed pivot means on saidframe with the other end of said lever means being connected to saidoperating member so as to normally be movable thereby; said part of saidlever means cooperating with said toggle means being disposed betweensaid fixed pivot means and the connection between said lever means andsaid operating member.

2. A circuit breaker as set forth in claim 1 in which one end of themain spring means is connected to the operating member and the other endthereof is connected to the knee of the toggle means; said operatingmember being mounted to said frame on another fixed pivot means.

3. A circuit breaker as set forth in claim 1 in which the frame includesspaced side walls between which said toggle means is disposed; saidlever means including first and second levers disposed adjacent to andmovable parallel to the respective side walls.

4. A circuit breaker as set forth in claim 3 in which the operatingmember is generally of inverted U-shape having first and second armsconnected at their upper ends by a web to which the main spring means isconnected; said arms at their lower ends being mounted to the respectiveside walls on another fixed pivot means.

5. A circuit breaker as set forth in claim 4 in which the first andsecond levers are connected to the respective first and second arms.

6. A circuit breaker as set forth in claim 5 in which individualcooperating pin-slot means connect the levers to the respective arms.

7. A circuit breaker as set forth in claim 6 in which the levers aredisposed outboard of said side walls and the side walls are disposedbetween the arms of the operating member.

8. A circuit breaker as set forth in claim 7 in which the ends of saidlevers connected to the arms of the operating member are interposedbetween said arms and the side walls of the frame.

9. A circuit breaker as set forth in claimB in which the connectionbetween each of the first and second levers and the respective first andsecond arms includes a pin extending outward from the lever into a slotin the arm.

1. A circuit breaker including cooperating contact means, an overcentertoggle mechanism for moving said contact means between open and closedpositions, and a handle operable between circuit breaker ON and OFFpositions corresponding to the respective open and closed positions ofsaid contact means; said mechanism including toggle means operativelyconnected to said contact means, main spring means operatively connectedto said toggle means to furnish opening and closing forces for saidcontact means, and an operating member connected to said handle andmovable therewith to change the relative positions of the line of actionof said means and the knee of said toggle means for driving the togglemeans overcenter thereby opening and closing said contact means; pivotedlever means connected to said operating member and having a partcooperating with said toggle means to block movement of said lever meansin a first direction until said toggle means is collapsed in a contactmeans opening direction; with movement of said lever means in a firstdirection being blocked by said toggle means, said lever means actingthrough said operating member restraining said handle from moving to itssaid OFF position; said mechanism also including a frame; one end ofsaid lever means being pivotally mounted to fixed pivot means on saidframe with the other end of said lever means being connected to saidoperating member so as to normally be movable thereby; said part of saidlever means cooperating with said toggle means being disposed betweensaid fixed pivot means and the connection between said lever means andsaid operating member.
 2. A circuit breaker as set forth in claim 1 inwhich one end of the main spring means is connected to the operatingmember and the other end thereof is connected to the knee of the togglemeans; said operating member being mounted to said frame on anotherfixed pivot means.
 3. A circuit breaker as set forth in claim 1 in whichthe frame includes spaced side walls between which said toggle means isdisposed; said lever means including first and second levers disposedadjacent to and movable parallel to the respective side walls.
 4. Acircuit breaker as set forth in claim 3 in which the operating member isgenerally of inverted U-shape having first and second arms connected attheir upper ends by a web to which the main spring means is connected;said arms at their lower ends being mounted to the respective side wallson another fixed pivot means.
 5. A circuit breaker as set forth in claim4 in which the first and second levers are connected to the respectivefirst and second arms.
 6. A circuit breaker as set forth in claim 5 inwhich individual cooperating pin-slot means connect the levers to therespective arms.
 7. A circuit breaker as set forth in claim 6 in whichthe levers are disposed outboard of said side walls and the side wallsare disposed between the arms of the operating member.
 8. A circuitbreaker as set forth in claim 7 in which the ends of said leversconnected to the arms of the operating member are interposed betweensaid arms and the side walls of the frame.
 9. A circuit breaker as setforth in claim 8 in which the connection between each of the first andsecond levers and the respective first aNd second arms includes a pinextending outward from the lever into a slot in the arm.